The most suspicious of about 2500 potential suspects in the Zodiac case, Allen could not be proven to be connected as “the forensic technology of the times was not advanced enough to nail any one of them conclusively” (Jake Wark). There are also connections made to Allen through things such like the ciphers left by the Zodiac Killer (see Button Letter Cipher).
With an I.Q of 137, Allen skipped three grads and continued on to Vallejo University where he majored in art and literature. After graduating from Vallejo, he joined the navy. This however was short lived and he was dishonorably discharged for an unspecified reason December 27, 1957 – the same year he enlisted. He later received employment “as an elementary-school teacher in California’s Calaveras County at the time of the Bates murder, by the time his employment ended in late March 1968 Allen had used only one of 19 available sick days. The day Allen was absent was Nov. 1, 1966 (ZodiacKiller).This date stands out because Cheri Jo Bates was murdered the previous night.
Besides than having suspicious alibis, Allen seems to be a likely suspect because of other crimes. He had been fired from two teaching positions for having a gun on school ground and molesting a female student, let go from a janitorial job for threatening students, and finally arrested when “Allen’s problem with children had apparently led him to molest a young boy” (zodiackillerfacts). For this last crime he received only two years in a hospital and subsequent probation.